ports/sysdeps/m68k/m680x0/fpu/e_scalb.c

   1 /* Copyright (C) 1997-2014 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Andreas Schwab <schwab@issan.informatik.uni-dortmund.de>.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library.  If not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <math.h>
  20 #include <math_private.h>
  21 #include "mathimpl.h"
  22
  23 #ifndef SUFF
  24 #define SUFF
  25 #endif
  26 #ifndef float_type
  27 #define float_type double
  28 #endif
  29
  30 #define CONCATX(a,b) __CONCAT(a,b)
  31 #define s(name) CONCATX(name,SUFF)
  32 #define m81(func) __m81_u(s(func))
  33
  34 float_type
  35 s(__ieee754_scalb) (float_type x, float_type fn)
  36 {
  37   float_type retval;
  38   unsigned long x_cond = __m81_test (x);
  39   unsigned long fn_cond = __m81_test (fn);
  40
  41   if ((x_cond | fn_cond) & __M81_COND_NAN)
  42     return x * fn;
  43
  44   if (fn_cond & __M81_COND_INF)
  45     {
  46       if (!(fn_cond & __M81_COND_NEG))
  47         return x * fn;
  48       else if (x_cond & __M81_COND_ZERO)
  49         return x;
  50       else
  51         return x / -fn;
  52     }
  53
  54   if (m81(__rint) (fn) != fn)
  55     return (x - x) / (x - x);
  56
  57   __asm ("fscale%.x %1, %0" : "=f" (retval) : "f" (fn), "0" (x));
  58   return retval;
  59 }
  60 strong_alias (s(__ieee754_scalb), CONCATX (s(__scalb), _finite))